MOXIE microwaved Mars air into oxygen, but now it's time for a breather

Concept will need to be scaled up to keep more than a small dog alive

NASA has called time on the oxygen-generating experiment bolted to its Mars Perseverance rover.

The Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE), a device roughly the size of a microwave oven, was designed to extract oxygen from the atmosphere of Mars. During its time on the red planet, it has produced 122 grams of the stuff. Or, according to NASA, approximately what a small dog breathes in 10 hours.

MOXIE has been run 16 times, hitting a peak of 12 grams of oxygen per hour. Its final run was on August 7, when it produced 9.8 grams. Boffins at NASA and JPL said they are delighted with MOXIE's performance. The 12 grams per hour was twice as much as NASA's original goals and the device has operated in various conditions throughout the Martian year.

However, all good things must come to an end, and last week it was announced that MOXIE operations were concluding.

Created by engineers and scientists from the Massachusetts Institute of Technology (MIT), MOXIE used an electrochemical process in which oxygen was extracted from carbon dioxide pumped in from Mars' atmosphere.

The process was slow; the incoming air was filtered to remove dust and then compressed and heated to 800°C (1,470°F). Oxygen could then be extracted and tested before being released back into the atmosphere. It took two hours to get the unit warmed up before the process could begin.

MOXIE was a slightly unusual payload for the science-focused Perseverance rover and was aimed at human exploration. It showed that it would be possible for a crew to survive on Mars as well as depart home using resources on the surface. In-situ resource utilization (ISRU) is a hot topic within the corridors of NASA and its partners as scientists ponder how longer-term missions might work.

NASA noted that the most important use of oxygen – as well as keeping the crew alive – would be as propellant for rockets. It would, however, be required in substantial quantities.

"MOXIE has clearly served as an inspiration to the ISRU community," said the instrument's principal investigator, Michael Hecht of MIT. "It showed NASA is willing to invest in these kinds of future technologies. And it has been a flagship that has influenced the exciting industry of space resources."

Despite the experiment's success and the design lessons learned, there are no plans for a MOXIE 2.0. Instead, the next step will be a full-scale system that includes a MOXIE-like oxygen generator and a way of liquifying and storing the oxygen generated. ®

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